Town & Country V6-3.8L VIN L (2006)
Seat Occupant Sensor: Description and Operation
Seat Weight Bladder And Pressure Sensor
Vehicles equipped with the Occupant Classification System (OCS) have a seat weight bladder and pressure sensor unit that is integral to the passenger
front seat cushion. The bladder is sandwiched between the seat cushion pan and seat cushion foam.
The bladder consists of two sheets of an elastomeric material and a molded plastic elbow fitting. The two sheets of material are sealed together around
their perimeter and heat staked to each other at numerous regular points within their field. The elbow fitting passes through a clearance hole in the seat
cushion pan. The bladder is then filled with a silicone fluid to become a pliable, quilted membrane.
Under the seat cushion a short tube is securely clamped at one end to the bladder nipple, and at the other end to a nipple on the electronic pressure
sensor. The sensor mounts on a clip attached to the seat cushion pan.
WARNING: THESE COMPONENTS ARE NOT REPLACEABLE SEPARATELY FROM THE SEAT CUSHION FOAM. WHEN
REPLACED AS AN ASSEMBLY, THE COMPLETE SERVICE KIT (SEAT CUSHION, BLADDER/SENSOR, OCM, AND NEW WIRING
HARNESS) MUST BE USED.
The seat weight bladder and pressure sensor unit is designed to sense the relative weight of a load applied to the passenger front seat cushion, which
provides a logic input to the microprocessor of the Occupant Classification Module (OCM). When a load is applied to the seat cushion, fluid within the
bladder becomes pressurized. These changes in bladder fluid pressure are measured by the pressure sensor under the seat cushion through the bladder
tube. As the pressure within the bladder changes, the circuitry of the pressure sensor changes the output voltage of the sensor.
The pressure sensor receives a nominal five volts and a ground through hard wired circuits from the OCM. The OCM then monitors the pressure sensor
output voltage on the Programmable Communication Interface (PCI) data bus circuit.
WARNING: THESE COMPONENTS ARE NOT REPLACEABLE SEPARATELY FROM THE SEAT CUSHION FOAM. WHEN
REPLACED AS AN ASSEMBLY, THE COMPLETE SERVICE KIT (SEAT CUSHION, BLADDER,/SENSOR, OCM, AND NEW WIRING
HARNESS) MUST BE USED.
To properly diagnose the seat weight bladder and pressure sensor, its communication with/between the OCM, and all other components within the OCS,
use a scan tool and the appropriate diagnostic information.
